Pressure sensor 2.008-spring-2003

Surface Micromachining Deposit sacrificial layer Pattern anchors Deposit/pattern structural layer Etch sacrificial layer 2.008-spring-2003

Surface micromachining Structure sacrificial etchant 􀂄  Polysilicon Silicon dioxide HF 􀂄  SiNx PSG HF 􀂄  Silicon dioxide polysilicon XeF2 􀂄  SiNx polysilicon XeF2 􀂄  Aluminum photoresist oxygen plasma 2.008-spring-2003

Residual stress gradients More tensile on top More compressive on top Just right! 2.008-spring-2003

Clean Room 􀂄  Gowning with bunny suit 􀂄  Class 1, 10, 100 A salt grain on a chip 2.008-spring-2003

Class of clean rooms 􀂄  Class 1 means one speckle of 0.5 μ partical in one ft3. 􀂄  Class 10, 100, 1000 􀂄  HEPA filter, AHU 2.008-spring-2003

Air Filters 􀂄  HEPA (High Efficiency Particulate Air) filters 􀂄  High efficiency, low Δp, good loading characteristics 􀂄  Glass fibers in a paper like medium 􀂄  97% retainment of incident particles of 0.3 μm or larger 2.008-spring-2003

Class of clean rooms Class Temp tolerance tolerance 2.008-spring-2003

Particles Class Federal Standard 209; Number of particles per cubic foot 2.008-spring-2003

Toxicity 􀂄  TLV (Threshold Limit Value) 􀂄  Upper limit material concentration that an average healthy person can be exposed without adverse effects, ppm or mg/m3 􀂄  Notorious Poisons 􀂄  CO (100 ppm), CO2 (5000 ppm), HCN (110 ppm), H2S (10 ppm) 􀂄  SO2 (5 ppm), NH3 (50 ppm) 􀂄  Arsenic trioxide AS2O3 (0.1g fatal) 􀂄  Hg (0.1 ppm via skin contact) 􀂄  All material are toxic in sufficient quantity, 5g caffein is fatal. 2.008-spring-2003

MEMS Applications 2.008-spring-2003

Display Technologies Market Screen Leader Size R.& D. Issues 􀁺 ● HDTV for 60” ~ 80” Home Theater 􀁺 ● Digital Presentation for 100 ” ~ 300” Projector 􀁺 ● Key Factor : Brightness 2.008-spring-2003

Brightness of Projection Displays lux = lumen / m2

DIGITAL MICROMIRROR DEVICE & DLP TM PROJECTOR PHOTONICS AND MICROMACHINING 1st Optical MEMS device DIGITAL MICROMIRROR DEVICE & DLP TM PROJECTOR 96365-39 CORPORATE RESEARCH & DEVELOPMENT

DMD Optical Switching Principle DMD Mirror on/off ± 10o Texas Instruments’s Technical Journal: Vol. 15, No. 3, July-Sept. 1998. 2.008-spring-2003

DMD Cell Structure 2.008-spring-2003 Texas Instruments’s Technical Journal: Vol. 15, No. 3, July-Sept. 1998. 2.008-spring-2003

TMA 2.008-spring-2003

Light Modulation of TMA Thinfilm Micromirror Array 2.008-spring-2003

Pixel Architecture Post contact to actuator Mirror Via contact to MOS Top Electrode PZT Bottom Electrode Supporting Layer Common Electrode Anchor Drain Pad Gate Line Source Line 2.008-spring-2003

Electronics) Piezoelectric TMA vs DMD DMDTM (Texas Instrument) Electrostatic TMATM (Daewoo Electronics) Piezoelectric Actuation 0o ~ 3o (continuous) Tilting Angle -10o, 0o, +10o Linear Simple On/Off Complex Gray Scale Control • Fatigue • Sticking • High Cost • Uniformity Drawbacks 2.008-spring-2003

Micromirror Arrays XGA 1024 X 768 786,432 pixels VGA 640 X 480 2.008-spring-2003

Mirror Flatness (VGA) 2.008-spring-2003

Coupled Natures of Thin Film Processes 􀂄  Forward coupling 􀂄  Step coverage, confromality 􀂄  Backward coupling 􀂄  Temperature dependent microstructural degradation 􀂄  Over/under etch, etch stop control 􀂄  Side attack, Passivation breakage 2.008-spring-2003

Evolution of TMA Pixels 2.008-spring-2003

MIT Bow-actuator Nick Conway, MS 2003 End effector Piezoelectric Amplifiers Released 4-bar linkage design Fixed substrate 2.008-spring-2003

Design of nanopipette (2): In-line array of nanopipettes 􀂄  Massive Parallel Nanopipette Array by In- plane Scanning Probe Systems 􀂄  Integration with Microfluidic channels 􀂄  Integration of nanopipettes in AFM in an 100 x 100 array Single nanopipette 2.008-spring-2003

Photonic crystal modeling Microcavity waveguide finite-difference time-domain 1 mesh 2.008-spring-2003

Photonic band gap microcavity waveguide processing 􀂃  design matrix of various geometries: defect lengths, waveguide width, d/a, number of holes 􀂃  Nanofabrication: 􀂃  SiNx mask1 /w electron-beam 􀂃  Proximity pattern transfer to resist 􀂃  130 nm minimum features 􀂃  Hard mask from Cr lift-off 2 􀂃  Optimized Si RIE 1 J. Ferrera, NanoStructures Laboratory, MIT. 2 J. Foresi, Kimerling group, MIT. 2.008-spring-2003

Design Domains What How 􀂄  Design is a mapping process 􀂄  From “What” to “How” 􀂄  Small scale systems design What How 2.008-spring-2003 N. P. Suh, Axiomatic Design, Oxford